The invention relates to forms for the pouring of concrete or the like. Such forms are used to assemble so-called formworks or shutterings.
A form for use in shutterings is often quite heavy and bulky. The bulk and weight are attributable, at least in part, to the provision of frames which are adjacent the marginal portions of the panels of such forms and serve to stiffen the panels as well as to rest on a support (e.g., on the ground or on the floor) or to abut the frames of adjacent forms in an assembled framework. The frame of a form is normally hollow and includes an outer wall which extends from one side of the marginal portion of the panel and the outer side of which comes. into contact with a support or with the outer wall of the frame on a neighboring form when the forms are in actual use. As a rule, the outer wall of the frame extends at right angles to the panel.
German Pat. No. 34 29 304 to Schliephacke discloses a form wherein the outer wall of the frame is provided with an elongated recess which is remote from the panel and is intended to receive the working end of a crowbar serving to lift the form and/or to adjust the position of the form relative to the adjacent form or forms. A drawback of the patented frame is that the recess weakens that (outer) wall of the frame which takes up the major part of stresses when the form is in use. Thus, if the form is set up to rest on the outer wall of the bottom section of its normally rectangular frame, such outer wall abuts the floor or the ground and carries the entire weight of the form. Moreover, the recess in the outer wall of the frame contributes to a reduction of the overall area of the exposed outer side or surface of such outer wall. Therefore, if the outer wall is to sealingly abut the outer wall of an adjoining frame or a support, the area of sealing engagement with the adjoining frame or with the support is relatively small so that freshly poured concrete is likely to escape from the cavity which is defined by the assembled framework for reception of concrete.
A frame is normally provided on a very heavy and bulky form in order to stiffen a relatively large concrete-contacting panel. If a crowbar is used to lift a very heavy form, and the working end of the crowbar is inserted into a recess which is provided in the outer wall of the frame at a considerable distance from the marginal portion of the panel, the crowbar is likely to cause at least some deformation of the engaged outer wall (e.g., during lifting of the form off a support) as well as of that section or those sections of the same frame which are adjacent the frame(s) of the neighboring form(s). This can result in the development of clearances which permit freshly poured concrete to escape between neighboring forms. The danger of undesirable deformation of certain sections of or of an entire frame is particularly pronounced after repeated lifting and/or other shifting of a relatively heavy form by resorting to a crowbar or to an analogous tool.
Though the recess in the outer wall of the frame which is disclosed by Schliephacke contributes to convenience of insertion of the working end of a tool, its drawbacks often outweigh its advantages, especially when the form is very heavy so that its frame and its panel are likely to undergo extensive deformation when the recess receives the working end of a crowbar or a like tool. Proposals to overcome the drawbacks of the patented frame by increasing the thickness of its walls have met with little success because this contributes to the bulk, weight and cost of the form and renders the adjustment of the form in a formwork or shuttering even more difficult and time-consuming. Moreover, this necessitates the exertion of an even greater force with attendant increased danger of deforming the frame in spite of its increased bulk and strength.